Migrant workers gather with their children along the tracks of the Denver & Rio Grande railroad in La Jara, Colorado in Conejos County. Their possessions, including bedframes, cabinets, wardrobes, tables, chairs, and kitchen utensils are gathereed...

Large wood buckets stand in the foreground in this interior view of the Buell Consolidated Gold Mining & Milling Company in Mountain City on the outskirts of Central City, a large mining community in Gilpin County, Colorado.

Mill buildings in Boulder, Colorado, are of brick and corrugated tin, and have gable, flat, mansard (with dormers), or monitor roofs. Full burlap sacks, brooms, and bales of straw are on the wooden dock, fronted by bare trees with stumps painted...

Dark smoke pours from the Alamosa Milling & Elevator Co. in Alamosa County, Colorado. Several men in suits and hats, and two in white work clothes, pose on a platform with a cart loaded with white sacks of flour. Another man in a suit stands alone...

Reproduction of a half tone shows a wooden building at the camp serving the Fourth of July mine, Boulder County, Colorado. The mine is owned and operated by the Consolidated Copper Mining, Milling, and Smelting Company. The building is a single...

View of the Sunnyside Mining & Milling Company, subsidiary of the United States Refining & Mining Company, at Eureka, San Juan County, Colorado; shows mine processing sheds on a hillside, with water towers, smokestacks, and tailings. Houses are by...

View of the Sunnyside Mining & Milling Company, subsidiary of the United States Refining & Mining Company, at Eureka, San Juan County, Colorado; shows mine processing sheds on a hillside, with water towers, smokestacks, and tailings. Houses are by...

A man wearing a suit leans against a wood post inside a stamp mill, possibly the Buell Consolidated Gold Mining & Milling Company in Mountain City on the outskirts of Central City in Gilpin County, Colorado. A small group of men stands behind him...

Artist's rendering, Monarch, in Chaffee County, Colorado, shows dwellings, commercial buildings, a tramway, railroad cars (engine, freight and ore cars) on tracks, and a milling structure. Monarch was founded in 1878 lasted until the silver panic...

View of the Golden Gilpin Gold Mill located 1 mile north of Black Hawk, Colorado on Colorado Highway 119. The structure is the remaining example of Black Hawk's milling industry from the 1870s when the area was the ore processing center for the...

Monarch, founded in Chaffee County, Colorado in 1878, consists of log or frame dwellings and commercial buildings lining dirt street. Surrounding hills are covered in felled timber; a tramway climbs the slopes to a mine higher up. Freight and ore...

Saints John, Summit County, Colorado, consists of frame dwellings at the base of tree covered slopes. A square, masonry smokestack is to one side. Some milling was done here as part of the Chalk Creek mining district.

View of the waterfront of San Francisco and San Francisco Bay, California. Steamboats are moored at piers nine, seven, and five. Tall masted ships are moored near the Roslyn Coal Company dock and the American Milling Company pier. Shows smoke above...

View of the waterfront of San Francisco and San Francisco Bay, California. Tall masted ships are moored near wood-covered piers. Industrial buildings including the American Milling Company buildings line the shore. Shows houses and commercial...

and awnings on the next windows west are striped and dome shaped. A sign between them reads: Manitou Springs Natural Foods. The next building west has a box shaped canopy with light bulbs along the perimeter, and people are milling beneath it. The...

View of Boulder, Colorado; shows the sandstone courthouse, Masonic Temple, and Methodist Church, with cupolas, towers, and pediments. Letters on the side of the Boulder Milling Company read: "Lily White Flour." University Avenue is a dirt street,...

in the left background. Fourteen men reportedly drowned in the Sleepy Hollow Mine in 1895 when water from an older and deeper mine burst through the wall between the two.; The shafthouse of the Gregory Buell Consolidated Mine and Milling Company...

Wooden beams, drive belts, and hanging lamps with frosted glass shades borne on curving rods fill the interior of the Boulder Milling and Elevator Company in Boulder, Colorado. Metal sifting cabinets with hoppers and flywheels are against the...

View of the Shenandoah-Dives mine aerial tramway in Arrastra Basin, San Juan County, Colorado; shows a steel tower and cables, a ranch house, and Boulder Mountain. Structures for milling gold, silver, copper, lead, and zinc are in the Animas River...

New Montrose Flour Milling Company buildings are next to the Denver and Rio Grande railroad tracks in Montrose, Colorado. Three rail cars are next to the mill, other cars loaded with coal are on a separate track. Automobiles are parked in front of...

View of the Cooper Building at the northwest corner of 17th (1009 Seventeenth) and Curtis streets in downtown Denver, Colorado. The building was designed by Frank E. Edbrooke in 1892 and was named for former Gov. Job A. Cooper. The Denver National...

Interior view of an Argo Smelting Works building, owned by the Boston and Colorado Smelting Company, Denver, Colorado, shows a chimney surrounded by gutters emanating from a furnace. One of the furnace doors is open as a man uses a long steel rod...